<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
    <style>
        ul {
            width: 100%;
            list-style: none;
            margin: 0;
            padding: 0;
        }
        li{
            float: left;
            width: 20%;
            background-color: red;
            font-size: 30px;
        }
        li:nth-child(2) {
            background-color: blue;
        }
    </style>
</head>
<body>
    <ul>
        <li>1</li>
        <li>2</li>
        <li>3</li>
        <li>4</li>
        <li>5</li>
    </ul>
</body>
</html>